Process for producing lubricating oils



Dec. 7, 193 7.

U. B. BRAY E T AL PROCESS FOR PRODUCING LUBRICATING OILS original Filed Feb. 2S, 1932 63 .'x/czporcror1N 62 22 Errac/'on 60 20 58 /61 .D :Sgm 66` Paw @can er' Q22:

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ATTORNEY.

Patented Dec. 7, 1937 PROCESS FOR PRlIIlESCmG. LUBRICATLNG I Uli-ic B. Bray, Palos Verdes Estates, and Claude v E. Swift, Glendale, Calif., assignors to Union Oil Company of California, Los Angeles, Calif., a corporation of California Original application February 23, 1932, Serial No.

594,605. Divided and this application 4, 1935, Serial No. 9,314

7 Claims.

`This invention relates to a process for the production of lubricating oil. More specifically, it relates to a process for the production of lubricating oil from crude oil containing asphalt, and

March which have sayboit universal viscosities' above 400-500 seconds at 100 F. It is safe to say that no oil containing asphalt can be topped to the .point where fractions above 400-500 seconds, Sayis a division of our copending application Serial bolt universal viscosity at 100 F. are vaporized 5 No. 594,605. flied February 2.3, 1932. without a degeneration of those characteristics of One of the distinctive characteristics of alubrithe paraffin hydrocarbons which impart to the eating oil is its viscosity. For many purposes oil a low temperature viscosity susceptibility. lubricants are preferred which exhibit aminimum During the distillation of the heavy` oils in the 10 variation in viscosity with variations in tempresence of asphalt some change in molecular 10 perature, i. e., have low viscosity temperastructure or configuration takes place which is ture susceptibility. It is generally known that attended by .a change of viscosity temperature the viscosity of lubricating oil produced from characteristics. This behavior is lthought to be Western crude, such as California asphalt base due to pyrolytic reactions which are catalyzed by crudes, that is, crude containing asphalt ics the presence of asphalt. The above discovery is 15 more with change in temperature than do lubrimade the subject matter of the application of eating oils produced from paraffin base crudes. Ulric B. Bray, vSerial No. 466,189, led July 7, That is, if two such oils have the same viscosity 1930. l at 100 F., the Westernfoil will have a much lower In order to preserve the inherent characterviscosity at 210 F. than will the parafn base oil. istics of the lubricating oil components of asphal- 20 This change in viscosity with temperature is tic crude oil which are impaired by distillation sometimes called the temperature susceptibility methods, as previously described, we have in of an oil. One of the characteristics of Westernv accordance with the process of the above applicalubricating oils, as manufactured by present tion caused the separation of part of the asphalt methods, is that they are distillates, that is, are from the oil under conditions which are not de- 25 vaporized from crude oil and condensed. Lubristructive to the inherent viscosity temperature eating oils produced from parain base oils, concharacteristics of the oils present. As a means taining substantially no asphalt, are generally of attaining this end, a portion of the asphalt is produced by rst distilling light oils overhead, separated from the oil by means of solvents which including the kerosene and gas-oil and also taking are capable of partially separating the asphalt 30 i overhead light lubricating oils called neutrals from'the oil. Such solvents as naphtha or gasohaving a viscosity in the neighborhood of 100-200 line may be employed advantageously to cause the seconds, Saybolt universal at 100 F., leaving an partial separation of the asphalt from the oil and undistilled residue termed bright stock. The especially naphtha or gasoline which has been oils of various viscosity are made by blending previously subjected to treatment with liquid sul- 35 these neutrals and bright stock in any desired phur dioxide. Furthermore, we may employ light proportion to obtain the desired viscosity. liquid hydrocarbons which are vaporous at ordi- It has been observed by one of us that many nary temperature and pressure. Light liquid oils containing asphalt and wax are mixtures of hydrocarbons recovered during the stabilization hydrocarbons analogous both to the hydrocarbons of casinghead gasoline, such as ethane, propane, 40 present in parailinA base oils and those present in butano and isobutane or mixtures of these comasphalt base oils. It has further been observed ponents may be employed under pressure to carry by one of us that during the heating of an oil conout the partial separation of the asphalt from the taining asphalt, the asphalt apparently induces oil. However, for most purposes a solvent which certain chemical and perhaps certain physical has a vapor pressure at ordinary temperature 45 reactions at relatively 10W temperatures which lower than atmospheric pressure is very satisfactend to destroy the inherent low viscosity terntory, for example, a naphtha or a gasoline. perature susceptibility of the lubricating oil frac- Other solvents, such as alcohol, alcohol and tions. This apparent catalytic phenomena Seems gasoline, alcohol and ether, acetone and acetone to explain the observed changes, although we do and gasoline may be employed. 50 not wish to be understood as being bound by this In carrying out the step of partially separating theory. It has been observed that these temperathe asphalt from the oil, the oil is brought into tures at which the changes appear are below the intimate contact with one of the foregoing solvaporizing temperatures in batch distillation vents. The solvent dissolves all of the oil present (vacuum or steam) ofthe lubricating oil fractions but causes a portion of the asphalt present lto 55 precipitate. The precipitated asphalt is then removed from the solvent solution "of oil and remaining asphalt by settling, filtration. centrifugingor othermeans, obvious to the art, for the separation of solids from liquids.

Many lubricating oils obtained from crude oil or crude oil residuums by extraction with solvents -are composed of oils which have a relatively high viscosity temperature susceptibility and oils which have a relatively low viscosity temperature susceptibility. For convenience we will hereinafter refer to the oils which exhibit a low viscosity temperature susceptibility as paraillnoid" oils and to those which exhibit a high viscosity temperature susceptibility as non-paramnoid" oils.

This mixture of parafilnoid and non-parailinoid oils obtained by 'extracting asphaltic crude oil with naphtha, gasoline, or the other foregoing mentioned solvents may be separated by the use of solvent agents which will selectively dissolve out tbe non-paraiilnoid components. Solvents which are useful for this purpose are liquid sulphur dioxide, furfural, nitrobenzene. selenium owchloride, aniline or methyl formate. The use -of liquid sulphur dioxide has been found to be especially valuable as a solvent to separate this hydrocarbon mixture into its paraflinoid and nonpara'flinoid constituents. The sulphur dioxide not only dissolves the non-paramnoid hydrocarbons present but also removes as an extract the remaining asphalt present in the oil mixture.

Thus the products which result from the foregoing extraction consist of an extract having a higher temperature viscosity susceptibility than the oil undergoing extraction and a fraction insoluble in the solvent which possesses a lower temperature viscosity susceptibility than the oil undergoing extraction.

We have found it advantageous to carry out the separation of the parailinoid oil from the nonparafllnold oil and remaining oil in the presence of the solvent used to partially separate the asphalt from the crude oil. The oil dissolved in the solvent has a low viscosity and when treated with liquid sulphur dioxide separates into layers readily without emulsication diillculties which usually attend the sulphur dioxide extraction of undiluted oils. As stated above, we prefer to use a liquid sulphur dioxide extracted naphtha or gasoline as a solvent to cause partial separation of the asphalt present in the crude oil. Such a fraction aids materially in the extraction of the oil with liquid sulphur dioxide to cause the remaining asphalt present to dissolve in the liquid sulphur dioxide layer.

In a prior application, Serial No. 555,018, dated August 4th, 1931, we have described a process for the production of lubricating oil from asphaltic' residues by treating the residues with a light liquid hydrocarbon, such as propane, to separate the asphalt from the oil and then treating the propane solution of oil with liquid sulphur dioxide to separate the parafilnoid from the nonparafilnoid oils. We have discovered that it is unnecessary to obtain a substantially complete removal of the asphalt' from the oil prior to extraction with liquid sulphur dioxide for the separation of the paramnoid from the non-paraillnoid oils. By removing a 'maior portion of the asphalt present in the oil by the use of naphtha or gasoline and then subjecting the partially deasphaltized oil dissolved in one of the foregoing solvents to the solvent action of liquid sulphur dioxide the remaining asphalt present is removed along with the non-parafiinoid oil in the extract phase without any difficulty.

By using such solvents as naphtha or gasoline for removing asphalt from the oil instead of liquid propane we are able to eliminate the use oi' high pressure equipment which adds materially to the cost of operating the process.

While our process works satisfactorily with crude oil we sometimes find it 'desirable to remove the light oilfractions present by distillation prior to the treatment with the flrst solvent for the partial separation of the asphalt present. The distillation step may be employed to remove from the crude oil the naphtha, gasoline, kerosene and gas oil fractions prior to the extraction with suitable solvents for the partial separation of the asphalt present.

In some cases -we have found it more advantageous to use acid instead of solvents to obtain a partial separation of the asphalt from the crude oil prior to the separation of the paraillnoid from the non-parafflnoid fractions. The asphaltic oil is first contacted with a small quantity of sulphuric acid which coagulates a portion of the asphalt present. The coagulated asphalt is separated froml the partially refined oil and then the latter is separated by the aid of a solvent, such as liquid sulphur dioxide, into one fraction containing the paraillnoid oils and another fraction containing the non-parafilnoid oils and the remaining asphalt. Where the crude oil is too viscous to obtain a good separation of the acid reaction products from the remaining oil and asphalt, we sometimes ind it advisable to add a light diluent, such as liquid sulphur dioxide treated naphtha or gasoline. Thus the crude oil or crude oil residue may first be diluted with liquid sulphur dioxide 'treated naphtha or gasoline, treated with sulphuric acid to remove a portion of the asphalt present and then extracted with liquid sulphur dioxide for the separation of the parailinoid oil from the non-parailinoid oil and remaining asphalt.

It is, therefore, an object of our invention to isolate from crude oil those oils having characteristics which impart to it a low viscosity temperature susceptibility typical of a paraflln base oil.

Itis another object of our invention to partially separate the asphalt from asphalt containing oil and then separate the paraillnoid oil from the non-paraillnoidoil and remaining asphalt; employing a method of separating the oils and asphalt which will not change or impair the inherent characteristics of the oils from the form in which they exist in the original crude oil.

It is another object of our invention to extract oil containing asphalt with a first solvent to obtain a partial separation of the asphalt present. Extract the oil dissolved in the first solvent containing the remaining asphalt with a second solvent capable of separating the parafilnoid oils from the nonparaiilnoid oils and remaining asphalt.

It is another object of our invention to extract oils containing asphalt with gasoline to obtain a partial separation of the asphalt present. Extract the gasoline solution of oil and remaining asphalt with liquid sulphur dioxide to separate the paraillnoid oils from the non-parafhnoid oils and remaining asphalt, and then separate the gasoline and sulphur dioxide from the oil fractions.

Fis. l is illustrative of one form of apparatus in which we may carry out our process.

Referring more particularly to Fig. 1, asphaltic oil in tank I passes by means of line 2 and valve 3 to pump 4 which forces it through line 5 into agitator I where it meets a stream of naphtha or gasoline coming from tank 6, through valve 1, pump 8 and line 9. 'I'he mixture of asphaltic oil and gasoline or naphtha is thoroughly mixed in agitator I0 and then passes by means of line I I into separator I2 where the asphalt precipitated by diluting the asphaltic oil with the solvent set,

tles out and is removed through valve I3 and line I4. The amount of asphalt which is precipitated by the gasoline or naphtha will depend largely upon the degree of dilution of the asphaltic oil with the light solvent. In general, we find that the use of three parts of solvent to one part of asphaltic oil will precipitate sufficient asphalt to enable us to operate the subsequent steps of our process without encountering emulsion difficulties due to the presence of excessive quantities of asphalt.

The partially deasphaltized oil dissolved in solvent is withdrawn from separator I2 through valve I5 and line I6 into pump I1 which forces it through line I8 into the bottom of treating column I9. The solvent solution of oil introduced in to the bottom of column I9 passes upward countercurrently to a stream of liquid sulphur dioxide introduced into the top of column I9 and coming from tank 30 through valve 3|, line 32, pump 33 and line 34. The liquid sulphur dioxide during its passage downward in column- -I9 through the ascending stream of oil dissolved in solvent removes from the latter oil constituents present which exhibit a high temperature viscosity susceptibility along with the remaining asphalt which Was not removed in separator I2. The sulphur dioxide carrying the high temperature viscosity susceptibility oil and asphalt is removed from treating column I9 through line 26, valve 21 into line 28 where it is combined with liquid sulphur dioxide containing high temperature viscosity susceptibility oil and asphalt removed from the treated oil in supplementary settling chamber 23 through line 24 and valve 25. The solution of oil and asphalt in liquid sulphur dioxide passes from line 28 into pump 29 which forces it through line 35 into evaporator 35 where by aid of steam introduced through closed coil 31 the sulphur dioxide is vaporized from the oil and asphalt. The vaporized sulphur dioxide is removed from evaporator 36 through line 38 and valve 39 into compressor 40 which forces it through line 4i into condenser 42 Where it is liquefied and passes by means of line 43 into liquid separator 44. 'The sulphur dioxide free oil and asphalt in evaporator 36 are removed through valve 1I and line 12 to storage tank 13.

The sulphur dioxide extracted oil dissolved in gasoline or naphtha is removed from treating column I9 through line 20, valve 2l and line 22 into supplementary settling chamber 23 where any entrained liquid sulphur dioxide is allowed to settle dout as has been previously described. The treated .oil dissolved in gasoline and carrying a small quantity of sulphur dioxide passes from supplementary settling chamber 23 through line 55, valve 58, line 51 to pump 58 which forces it through line 59 into evaporator 60 where by aid of steam introduced through closed coil BI the light solvent consisting of gasoline or naphtha and the sulphur dioxide present are vaporized. These vapors are removed through line 62, valve 53 and line 64 to compressor 65 which forces them through line 66 and line 4I to condenser 42 where they are liquefied and pass by means of line 43 into liquid separator 44. Due to the difference in specific gravitypf the liquid sulphur dioxide and the liquid gasoline or naphtha in separator 44 these liquids stratify. The gasoline or naphtha present is removed through line 50, valve 5I, line 52 to pump 53 which passes it back through line 54 to storage tank 6. The liquid sulphur dioxide in separator 44 is removed through line 45,'valve 46 and li e 41 tmpump 48 which forces it through line 49 ty liquid sulphur dioxide storage tank 30.

The treated oil having a low temperature viscosity susceptibility in evaporator 60 is removed through line 61, valve 68 and line 69 to storage tank 10.

The above is not to be taken as limiting, but merely illustrative of a mode of carrying out our invention, which We claim to be:

1. A process for thev production of lubricating precipitated asphalt from the oil and remaining .asphalt dissolved in gasoline, extracting the oil and remaining asphalt dissolved ingasoline with liquid sulphur dioxide to produce an oil fraction exhibiting a relatively low temperature viscosity susceptibility dissolved in gasoline and an oil fraction exhibiting a relatively high temperature viscosity susceptibility dissolved in liquid sulphur dioxide containing the remaining asphalt and subsequently separating the gasoline and sulphur dioxide from the oil fractions.

2. A process for the production of lubricating oil from oil containing asphalt which comprises distilling said oil to a temperature not exceeding 650 F., commingling the residual oil resulting from the distillation with gasoline to partially separate the asphalt from the residual oil, removing the separated asphalt from the gasoline solution of oil containing the remaining asphalt, extracting said gasoline solution of oil and remaining asphalt with liquid sulphur dioxide to produce a plurality of oil fractions one of which has a relatively high temperature viscosity susceptibility and another of which has a relatively low temperature viscosity susceptibility containing said remaining asphalt and subsequently separating the gasoline and sulphur dioxide from said fractions.

3. A process for the production of lubricating oil from oil containing asphalt which comprises distilling said oil to a temperature beyond which fractions would be vaporized having a Saybolt universal viscosity at .100 F. in excess of 400 seconds, commingling the residual oil resulting from the distillation with gasoline to partially separate the asphalt from the residual oil, removing the separated asphalt from the gasoline solution of oil containing the remaining asphalt, extracting said gasoline solution of oil and remaining asphalt with liquid sulphur dioxide to produce a plurality of oil fractions one of which has a relatively high temperature viscosity `susceptibility and another of which has a relatively low temperature viscosity susceptibility containing said remaining asphalt and subsequently separating the gasoline and sulphur dioxide from said fractions.

4. A process for the production of lubricating oil from oil containing asphalt which comprises treating said oil with gasoline to precipitate a portion of the asphalt from the oil, removing the precipitated asphalt from the oil and remaining asphalt dissolved in gasoline, extracting the oil and remaining asphalt dissolved in gasoline with a selective solvent for the asphalt and the fractions present in said oil which have a high temperature viscosity susceptibility and thereby separating said oil into two fractions, one of which contains oil exhibiting a relatively low temperature viscosity susceptibility and another of which contains oil exhibiting a relatively high temperature viscosity susceptibility and the remaining asphalt and separating said fractions.

5. A -process according to claim 4 in which the selective solventis nitrobenzene.

6. A process for the production of lubricating oil from oil containing asphalt which comprises treating said oil with petroleum naphtha to precipitate a portion of the asphalt from the oil, removing the precipitated asphalt from the oil and remaining asphalt dissolved in petroleum lnaphtha, extracting the oil and remaining asphalt dissolved in petroleum naphtha with a`se1ective solvent for the asphalt and the fractions present in said oil which have a high temperatureviscosity susceptibility and thereby separating said oil into two fractions, one of which contains oil 2,1o1,sos

exhibiting a relatively low temperature viscosity susceptibility and another of which contains oil exhibiting a relatively high temperature viscosity susceptibility and the remaining asphalt and separating said fractions.

'7. A process for the production of lubricating oil from oil containing asphalt which comprises treating said oil with petroleum naphtha to precipitate, a portion of the asphalt from the oil. removing the precipitated asphalt from the oil and remaining asphalt dissolved in petroleum naphtha, extracting the oil and remaining asphalt dissolved in petroleum nsphtha with nitrobenzene and thereby separating said oil into two fractions, one of which contains oil exhibiting a relativelylow temperature viscosity susceptibility and another of which contains oil exhibiting a relatively high temperature viscosity susceptibility and the remaining asphalt and separating said fractions. l

ULRIC B. BRAY. CLAUDE E. SWIFT. 

